iommu/amd: Add support for enabling/disabling IOMMU features

Add support for struct iommu_ops.dev_{enable/disable}_feat. Please note
that the empty feature switches will be populated by subsequent patches.
Signed-off-by: Wei Huang <wei.huang2@amd.com>
Co-developed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20240418103400.6229-4-vasant.hegde@amd.comSigned-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/amd/iommu.c

@@ -2791,6 +2791,32 @@ static const struct iommu_dirty_ops amd_dirty_ops = {
 	.read_and_clear_dirty = amd_iommu_read_and_clear_dirty,
 };
 
+static int amd_iommu_dev_enable_feature(struct device *dev,
+					enum iommu_dev_features feat)
+{
+	int ret;
+
+	switch (feat) {
+	default:
+		ret = -EINVAL;
+		break;
+	}
+	return ret;
+}
+
+static int amd_iommu_dev_disable_feature(struct device *dev,
+					 enum iommu_dev_features feat)
+{
+	int ret;
+
+	switch (feat) {
+	default:
+		ret = -EINVAL;
+		break;
+	}
+	return ret;
+}
+
 const struct iommu_ops amd_iommu_ops = {
 	.capable = amd_iommu_capable,
 	.domain_alloc = amd_iommu_domain_alloc,
@@ -2803,6 +2829,8 @@ const struct iommu_ops amd_iommu_ops = {
 	.is_attach_deferred = amd_iommu_is_attach_deferred,
 	.pgsize_bitmap	= AMD_IOMMU_PGSIZES,
 	.def_domain_type = amd_iommu_def_domain_type,
+	.dev_enable_feat = amd_iommu_dev_enable_feature,
+	.dev_disable_feat = amd_iommu_dev_disable_feature,
 	.default_domain_ops = &(const struct iommu_domain_ops) {
 		.attach_dev	= amd_iommu_attach_device,
 		.map_pages	= amd_iommu_map_pages,